Mower won’t start since changing battery and negative cable gets hot and smokes. Mower runs momentarily if spraying carburetor cleaner into intake, dies when spraying stopped. Already has new carburetor and plugs. Any help greatly appreciated.
First thing to check is the battery cables, wouldn’t be the first time someone has switched them around. Second is check the ground cable connection to the chassis, weak or dirty connection will cause cable to heat up. Third, this one I’m guessing at because you don’t tell us which engine you have, is the fuel solenoid opening with the key in the run position.
Mower magnetos are self energising so it will run without the battery at all provided the fuel solenoid is energised.
A hot wire signifies high current flowing through it and the most common cause for that is a bad connection at either end or an internally corroded wire .
NExt most common cause is a failed regulator allowing AC to be pumped into the battery
If the engine fires when you spray fuel into the carb you have spark. Did you check the connections, plus check the fuel solenoid as I stated earlier. I think you are assuming things are good without checking and testing them.
And the third thing that makes the wires hot is the battery or regulator hooked up backwards.
However usually that will cause the fuse to blow and in most cases cause the starter to turn backwards but I have seen at least one mower with a backwards wired battery & it would start , run for a few minutes then blow the fuse & stop.
The only other ones were old Greenfields that were fitted with both a pull & electric start engine
